[Jingle] Opinions about Coin

Saúl Ibarra Corretgé saul at ag-projects.com
Wed Apr 13 11:37:49 UTC 2011


First, sorry for breaking the discussion thread, I wasn't subscribed 
with this email address before.

On Tue, 2011-04-12 at 13:33 +0200, thiagoc wrote:
 > In short, Coin is definitely interesting for the following reasons:
 > * Does NOT require MUC support on client nor server
 > * It includes server side mixing, which might be required for most
 > conferences with more than 3 participants
 > * For mobile world, client side mixing and multiple streams handling
 > is out of question
 > * Matches current real life requirements
 > * It is easy to implement, that speeds up adoption

Full disclosure: My knowledge in this area is mainly due to my SIP 
background, and I enjoyed a nice discussion with Emil Ivov at FOSDEM 
about this, so I'll throw my 2 cents.

Having implemented a conferencing server with RFC4575 support (using 
SIP, but anyway) Coin makes more sense to me and I do agree with all 
points Thiago mentioned above:

- Needing cooperation from the client side is a bad idea, people with 
the cheapest Jingle client should be able to join the conference, though 
it may not be able to experience shiny features like RFC4575.

- Server side mixing might be a problem for some (what if the server 
fails...) but I think we have more to gain by doing it in the server: 
bandwidth and resources being the main reasons here. Not sure if this 
can be applied to XMPP, but in SIP we have the concept of 'cascading 
focus', that is, a conference server may join another conference server 
and all the data is aggregated by both, so participants see a full 
RFC4575 payload with the aggregated information of both servers. The 
number of servers may grow arbitrarily, so the load can be balanced and 
if a server fails only some participants will be dropped. Doing it 
server side also allows for stuff like scheduled conferences, for example.

- Interoperability with SIP: Being a SIP guy Coin made a lot of sense to 
me since it reuses existing standards to achieve same purpose in the 
XMPP world. Moreover, we plan to add XMPP gateway support, so being so 
symmetric with Coin things would just match and conferencing between 
XMPP and SIP mixed together would be far easier to implement IMHO.

That's my 2 cents.

Kind regards,

Saúl Ibarra Corretgé
AG Projects

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